What kind of bus driver allows such childish and awful behaviour inside their vehicle?! The moment one of those kids gets genuinely injured, she'll be just as guilty and responsible as the ones partaking, and competent authorities won't take kindly to this lack of ethic...
I'm genuinely sorry for the screams and bad times. Something similar happens to a loved one of mine, so I know how horrible it is. It might be a silly solution, but have you considered noise-cancelling headsets? They could help not only there, but anywhere where sound can get overwhelming.
There is also the option of taking another bus entirely, but I wouldn't want your schedules to be so drastically shifted just because of immature children...
